With development of wireless communications technologies, people's requirements on quality of service (QoS) of wireless communication are becoming higher. To provide different QoS, a Long Term Evolution (LTE) system maps different services to different tunnels, to implement different processing.
Several QoS characteristics are defined for the LTE system, where the QoS characteristics characterize upper limits for time delays of transmission of different types of user equipment data packets between a user equipment (UE) and a policy and charging enforcement function (PCEF) entity or policy and charging rules function (PCRF) entity. However, quality of service sensed by the UE is actually end-to-end experience. No matter how short a transmission delay between a UE and a PCRF entity is, if a transmission delay between a server and a packet data gateway (PGW) is excessively long, unsatisfactory experience of the UE is still caused. In addition, different from a previous second-generation wireless communications system, the LTE system supports only a packet-switched (PS) connection, and no longer supports a circuit-switched (CS) connection. However, no resource is reserved for the PS connection, and therefore, during implementation in an actual system, the transmission delay between the UE and the PCEF or PCRF entity cannot be guaranteed, and then QoS in a wireless communications process cannot be guaranteed.
The prior art provides a method for improving call quality during a bidirectional call. In this method, an information flow of a call is examined in a call process, such that at least one interaction characteristic of the call process is monitored, and then characteristics of a specific interaction characteristic are detected. A maximum end-to-end delay is determined according to the detected characteristics of the interaction characteristic, and the maximum end-to-end delay is introduced into the call; and on the premise that a delay permits, an operation for improving call quality is added, for example, forward error correction coding/decoding, and then call experience can be improved.
However, similar to a QoS characteristic defined for the LTE system, this method cannot ensure an end-to-end delay. In addition, in this method, an interaction characteristic of a call is monitored after the call starts, and therefore, adjustment of a call delay is merely adjustment in a small range. If a transmission network has a problem of poor transmission quality during call connection, this method cannot ensure quality of service either.